The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
Free tracker included with every download this week
What Does a BMI of 30 Mean for Women?
A BMI of 30 is classified as obese according to NHS guidelines. This means your weight relative to your height puts you at increased risk of several health conditions, including type 2 diabetes, heart disease, and high blood pressure. However, BMI is just one screening tool — it doesn't account for muscle mass, age, or where fat is stored on your body. Your GP can provide personalised advice about what your individual BMI means for your health and whether any support or lifestyle changes might be beneficial. Use our free BMI calculator above to check your exact BMI and explore your personal healthy weight range.
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Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
BMI Categories and Health Context
A BMI of 30 marks the threshold into the obese category (Class I) according to NHS guidelines. Here's how BMI is categorised:
- Underweight: below 18.5
- Healthy weight: 18.5–24.9
- Overweight: 25.0–29.9
- Obese (Class I): 30.0–34.9
- Obese (Class II): 35.0–39.9
- Severely obese (Class III): 40.0 and above
If you're a woman of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher health risks at lower weights — so a BMI of 30 would fall into a higher risk category for you. Use our free BMI calculator to determine your exact category and find your healthy weight range based on your height.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
BMI Limitations and What Else Matters
While BMI is a useful screening tool, it has important limitations. BMI doesn't distinguish between muscle and fat — athletes and people with high muscle mass may have a high BMI but low body fat percentage. It also doesn't account for where fat is stored; excess fat around the stomach (waist circumference) carries higher health risks than fat stored elsewhere.
The NHS also recommends measuring waist circumference alongside BMI: for women, over 80cm (31.5 inches) indicates increased risk, and over 88cm (34.5 inches) indicates high risk. Your GP can assess your overall health picture and discuss personalised options, which may include lifestyle support, dietary changes, or other interventions depending on your individual circumstances.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Is a BMI of 30 considered obese?
Yes, according to NHS guidelines, a BMI of 30 is classified as obese (Class I). This is the threshold where health risks from excess weight begin to increase significantly. However, BMI is one tool among many — your GP will consider your overall health, family history, and other factors when assessing your individual risk.
What health risks are associated with a BMI of 30?
A BMI of 30 increases risk of type 2 diabetes, cardiovascular disease, high blood pressure, sleep apnoea, and certain cancers. Even modest weight loss of 5–10% of your body weight can meaningfully reduce these risks. Your GP can discuss your individual risk factors and recommend appropriate support.
What's the healthy BMI range for women?
According to NHS guidelines, the healthy BMI range for women is 18.5 to 24.9. For women of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower threshold of 18.5 to 22.9 due to higher health risks at higher BMI levels.
How do I calculate my BMI if I'm a woman?
BMI is calculated as weight (kg) divided by height (metres) squared. For example, if you weigh 80kg and are 1.63m tall: 80 ÷ (1.63)² = BMI of 30.1. Use our free BMI calculator above to enter your height and weight — it works for all adults and accounts for UK measurements in stone and pounds.
Can I have a BMI of 30 and still be healthy?
While BMI is a useful screening tool, it doesn't tell the whole story. Waist circumference, fitness level, muscle mass, and blood pressure all matter. Some people with a BMI of 30 may have good cardiovascular fitness or lower waist measurements, which reduces risk. However, the NHS recommends discussing your personal situation with your GP to understand your individual health profile.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.